title: Quantitative evaluation and comparison of stress transmission characteristics of bar-clip and short coping overdenture attachments under dynamic loading: a photoelastic stress analysis.
abstract: BACKGROUND
  When two canine abutment teeth are used to support an overdenture prosthesis, optimal stress distribution to minimize forces to abutments is desired.
  
  
  OBJECTIVE
  This study used photoelastic stress analysis to compare the stress patterns generated around canine abutments using two different overdenture retainer designs.
  
  
  METHODS
  Two canine abutments were anchored in the photoelastic mandible and overdentures were fabricated using two different overdenture attachments. The fitting surface of dentures were lined with resilient layer of light bodied silicon rubberbase impression material to simulate oral mucosa. The attachments used were Bar-Clip and Short coping type. Verticalload of 5 to 50 lb was applied by jaw simulator. Resultant stress fringes were photographed and evaluated quantitatively.
  
  
  RESULTS
  Bar-Clip type of attachment transmitted more amount of stress than short coping type transmitted. There was gross difference in magnitude of stresses between two types of retainers.
  
  
  CONCLUSIONS
  As the retentivity of the attachment increased there was more stress concentration around the abutments.
authors.affiliation: Department of Prosthodontics, College of Dentistry, King Khalid University, Abha, Saudi Arabia. at1970c@yahoo.co.in
authors.forename: Alok
authors.initials: A
authors.lastname: Dwivedi
authors.forename: Rajesh
authors.initials: R
authors.lastname: Vyas
authors.forename: Anurag
authors.initials: A
authors.lastname: Gupta
mesh_terms: D000465:Algorithms; D001696:Biomechanical Phenomena; D001732:Bite Force; D002858:Chromium Alloys / Q000737:chemistry; D003481:Cuspid / Q000502:physiology; D000044:Dental Abutments; D003799:Dental Stress Analysis / Q000295:instrumentation; D003779:Denture Design; D003781:Denture Retention / Q000295:instrumentation*; D003824:Denture, Complete; D003828:Denture, Overlay; D006801:Humans; D008334:Mandible / Q000033:anatomy & histology; D008953:Models, Anatomic; D013314:Stress, Mechanical
chemical_list: D002858:Chromium Alloys